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// SPDX-License-Identifier: GPL-2.0-or-later/* *	common UDP/RAW code *	Linux INET6 implementation * *	Authors: *	Pedro Roque		<roque@di.fc.ul.pt> */ #include <linux/capability.h>#include <linux/errno.h>#include <linux/types.h>#include <linux/kernel.h>#include <linux/interrupt.h>#include <linux/socket.h>#include <linux/sockios.h>#include <linux/in6.h>#include <linux/ipv6.h>#include <linux/route.h>#include <linux/slab.h>#include <linux/export.h>#include <linux/icmp.h> #include <net/ipv6.h>#include <net/ndisc.h>#include <net/addrconf.h>#include <net/transp_v6.h>#include <net/ip6_route.h>#include <net/tcp_states.h>#include <net/dsfield.h>#include <net/sock_reuseport.h> #include <linux/errqueue.h>#include <linux/uaccess.h> static bool ipv6_mapped_addr_any(const struct in6_addr *a){	return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);} static void ip6_datagram_flow_key_init(struct flowi6 *fl6,				       const struct sock *sk){	const struct inet_sock *inet = inet_sk(sk);	const struct ipv6_pinfo *np = inet6_sk(sk);	int oif = sk->sk_bound_dev_if; 	memset(fl6, 0, sizeof(*fl6));	fl6->flowi6_proto = sk->sk_protocol;	fl6->daddr = sk->sk_v6_daddr;	fl6->saddr = np->saddr;	fl6->flowi6_mark = sk->sk_mark;	fl6->fl6_dport = inet->inet_dport;	fl6->fl6_sport = inet->inet_sport;	fl6->flowlabel = ip6_make_flowinfo(np->tclass, np->flow_label);	fl6->flowi6_uid = sk_uid(sk); 	if (!oif)		oif = np->sticky_pktinfo.ipi6_ifindex; 	if (!oif) {		if (ipv6_addr_is_multicast(&fl6->daddr))			oif = READ_ONCE(np->mcast_oif);		else			oif = READ_ONCE(np->ucast_oif);	} 	fl6->flowi6_oif = oif;	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));} int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr){	struct ip6_flowlabel *flowlabel = NULL;	struct inet_sock *inet = inet_sk(sk);	struct ipv6_pinfo *np = inet6_sk(sk);	struct ipv6_txoptions *opt;	struct in6_addr *final_p;	struct dst_entry *dst;	struct flowi6 *fl6;	int err = 0; 	if (inet6_test_bit(SNDFLOW, sk) &&	    (np->flow_label & IPV6_FLOWLABEL_MASK)) {		flowlabel = fl6_sock_lookup(sk, np->flow_label);		if (IS_ERR(flowlabel))			return -EINVAL;	}	fl6 = &inet_sk(sk)->cork.fl.u.ip6;	ip6_datagram_flow_key_init(fl6, sk); 	rcu_read_lock();	opt = flowlabel ? flowlabel->opt : rcu_dereference(np->opt);	final_p = fl6_update_dst(fl6, opt, &np->final);	rcu_read_unlock(); 	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);	if (IS_ERR(dst)) {		err = PTR_ERR(dst);		goto out;	} 	if (fix_sk_saddr) {		if (ipv6_addr_any(&np->saddr))			np->saddr = fl6->saddr; 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {			sk->sk_v6_rcv_saddr = fl6->saddr;			inet->inet_rcv_saddr = LOOPBACK4_IPV6;			if (sk->sk_prot->rehash)				sk->sk_prot->rehash(sk);		}	} 	ip6_sk_dst_store_flow(sk, dst, fl6); out:	fl6_sock_release(flowlabel);	return err;} void ip6_datagram_release_cb(struct sock *sk){	struct dst_entry *dst; 	if (ipv6_addr_v4mapped(&sk->sk_v6_daddr))		return; 	rcu_read_lock();	dst = __sk_dst_get(sk);	if (!dst || !READ_ONCE(dst->obsolete) ||	    dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {		rcu_read_unlock();		return;	}	rcu_read_unlock(); 	ip6_datagram_dst_update(sk, false);}EXPORT_SYMBOL_GPL(ip6_datagram_release_cb); int __ip6_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr,			   int addr_len){	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;	struct inet_sock	*inet = inet_sk(sk);	struct ipv6_pinfo	*np = inet6_sk(sk);	struct in6_addr		*daddr, old_daddr;	__be32			fl6_flowlabel = 0;	__be32			old_fl6_flowlabel;	__be16			old_dport;	int			addr_type;	int			err; 	if (usin->sin6_family == AF_INET) {		if (ipv6_only_sock(sk))			return -EAFNOSUPPORT;		err = __ip4_datagram_connect(sk, uaddr, addr_len);		goto ipv4_connected;	} 	if (addr_len < SIN6_LEN_RFC2133)		return -EINVAL; 	if (usin->sin6_family != AF_INET6)		return -EAFNOSUPPORT; 	if (inet6_test_bit(SNDFLOW, sk))		fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK; 	if (ipv6_addr_any(&usin->sin6_addr)) {		/*		 *	connect to self		 */		if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))			ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),					       &usin->sin6_addr);		else			usin->sin6_addr = in6addr_loopback;	} 	addr_type = ipv6_addr_type(&usin->sin6_addr); 	daddr = &usin->sin6_addr; 	if (addr_type & IPV6_ADDR_MAPPED) {		struct sockaddr_in sin; 		if (ipv6_only_sock(sk)) {			err = -ENETUNREACH;			goto out;		}		sin.sin_family = AF_INET;		sin.sin_addr.s_addr = daddr->s6_addr32[3];		sin.sin_port = usin->sin6_port; 		err = __ip4_datagram_connect(sk,					     (struct sockaddr_unsized *)&sin,					     sizeof(sin)); ipv4_connected:		if (err)			goto out; 		ipv6_addr_set_v4mapped(inet->inet_daddr, &sk->sk_v6_daddr); 		if (ipv6_addr_any(&np->saddr) ||		    ipv6_mapped_addr_any(&np->saddr))			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr); 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr) ||		    ipv6_mapped_addr_any(&sk->sk_v6_rcv_saddr)) {			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,					       &sk->sk_v6_rcv_saddr);			if (sk->sk_prot->rehash)				sk->sk_prot->rehash(sk);		} 		goto out;	} 	if (__ipv6_addr_needs_scope_id(addr_type)) {		if (addr_len >= sizeof(struct sockaddr_in6) &&		    usin->sin6_scope_id) {			if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id)) {				err = -EINVAL;				goto out;			}			WRITE_ONCE(sk->sk_bound_dev_if, usin->sin6_scope_id);		} 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))			WRITE_ONCE(sk->sk_bound_dev_if, READ_ONCE(np->mcast_oif)); 		/* Connect to link-local address requires an interface */		if (!sk->sk_bound_dev_if) {			err = -EINVAL;			goto out;		}	} 	/* save the current peer information before updating it */	old_daddr = sk->sk_v6_daddr;	old_fl6_flowlabel = np->flow_label;	old_dport = inet->inet_dport; 	sk->sk_v6_daddr = *daddr;	np->flow_label = fl6_flowlabel;	inet->inet_dport = usin->sin6_port; 	/*	 *	Check for a route to destination an obtain the	 *	destination cache for it.	 */ 	err = ip6_datagram_dst_update(sk, true);	if (err) {		/* Restore the socket peer info, to keep it consistent with		 * the old socket state		 */		sk->sk_v6_daddr = old_daddr;		np->flow_label = old_fl6_flowlabel;		inet->inet_dport = old_dport;		goto out;	} 	reuseport_has_conns_set(sk);	sk->sk_state = TCP_ESTABLISHED;	sk_set_txhash(sk);out:	return err;}EXPORT_SYMBOL_GPL(__ip6_datagram_connect); int ip6_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len){	int res; 	lock_sock(sk);	res = __ip6_datagram_connect(sk, uaddr, addr_len);	release_sock(sk);	return res;}EXPORT_SYMBOL_GPL(ip6_datagram_connect); int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr_unsized *uaddr,				 int addr_len){	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);	if (sin6->sin6_family != AF_INET6)		return -EAFNOSUPPORT;	return ip6_datagram_connect(sk, uaddr, addr_len);}EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only); static void ipv6_icmp_error_rfc4884(const struct sk_buff *skb,				    struct sock_ee_data_rfc4884 *out){	switch (icmp6_hdr(skb)->icmp6_type) {	case ICMPV6_TIME_EXCEED:	case ICMPV6_DEST_UNREACH:		ip_icmp_error_rfc4884(skb, out, sizeof(struct icmp6hdr),				      icmp6_hdr(skb)->icmp6_datagram_len * 8);	}} void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,		     __be16 port, u32 info, u8 *payload){	struct icmp6hdr *icmph = icmp6_hdr(skb);	struct sock_exterr_skb *serr; 	if (!inet6_test_bit(RECVERR6, sk))		return; 	skb = skb_clone(skb, GFP_ATOMIC);	if (!skb)		return; 	skb->protocol = htons(ETH_P_IPV6); 	serr = SKB_EXT_ERR(skb);	serr->ee.ee_errno = err;	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;	serr->ee.ee_type = icmph->icmp6_type;	serr->ee.ee_code = icmph->icmp6_code;	serr->ee.ee_pad = 0;	serr->ee.ee_info = info;	serr->ee.ee_data = 0;	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -				  skb_network_header(skb);	serr->port = port; 	__skb_pull(skb, payload - skb->data); 	if (inet6_test_bit(RECVERR6_RFC4884, sk))		ipv6_icmp_error_rfc4884(skb, &serr->ee.ee_rfc4884); 	skb_reset_transport_header(skb); 	if (sock_queue_err_skb(sk, skb))		kfree_skb(skb);}EXPORT_SYMBOL_GPL(ipv6_icmp_error); void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info){	struct sock_exterr_skb *serr;	struct ipv6hdr *iph;	struct sk_buff *skb; 	if (!inet6_test_bit(RECVERR6, sk))		return; 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);	if (!skb)		return; 	skb->protocol = htons(ETH_P_IPV6); 	skb_put(skb, sizeof(struct ipv6hdr));	skb_reset_network_header(skb);	iph = ipv6_hdr(skb);	iph->daddr = fl6->daddr;	ip6_flow_hdr(iph, 0, 0); 	serr = SKB_EXT_ERR(skb);	serr->ee.ee_errno = err;	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;	serr->ee.ee_type = 0;	serr->ee.ee_code = 0;	serr->ee.ee_pad = 0;	serr->ee.ee_info = info;	serr->ee.ee_data = 0;	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);	serr->port = fl6->fl6_dport; 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);	skb_reset_transport_header(skb); 	if (sock_queue_err_skb(sk, skb))		kfree_skb(skb);} void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu){	struct ipv6_pinfo *np = inet6_sk(sk);	struct ipv6hdr *iph;	struct sk_buff *skb;	struct ip6_mtuinfo *mtu_info; 	if (!np->rxopt.bits.rxpmtu)		return; 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);	if (!skb)		return; 	skb_put(skb, sizeof(struct ipv6hdr));	skb_reset_network_header(skb);	iph = ipv6_hdr(skb);	iph->daddr = fl6->daddr; 	mtu_info = IP6CBMTU(skb); 	mtu_info->ip6m_mtu = mtu;	mtu_info->ip6m_addr.sin6_family = AF_INET6;	mtu_info->ip6m_addr.sin6_port = 0;	mtu_info->ip6m_addr.sin6_flowinfo = 0;	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr; 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);	skb_reset_transport_header(skb); 	skb = xchg(&np->rxpmtu, skb);	kfree_skb(skb);} /* For some errors we have valid addr_offset even with zero payload and * zero port. Also, addr_offset should be supported if port is set. */static inline bool ipv6_datagram_support_addr(struct sock_exterr_skb *serr){	return serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6 ||	       serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||	       serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL || serr->port;} /* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL. * * At one point, excluding local errors was a quick test to identify icmp/icmp6 * errors. This is no longer true, but the test remained, so the v6 stack, * unlike v4, also honors cmsg requests on all wifi and timestamp errors. */static bool ip6_datagram_support_cmsg(struct sk_buff *skb,				      struct sock_exterr_skb *serr){	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||	    serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)		return true; 	if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)		return false; 	if (!IP6CB(skb)->iif)		return false; 	return true;} /* *	Handle MSG_ERRQUEUE */int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len){	struct ipv6_pinfo *np = inet6_sk(sk);	struct sock_exterr_skb *serr;	struct sk_buff *skb;	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);	struct {		struct sock_extended_err ee;		struct sockaddr_in6	 offender;	} errhdr;	int err;	int copied; 	err = -EAGAIN;	skb = sock_dequeue_err_skb(sk);	if (!skb)		goto out; 	copied = skb->len;	if (copied > len) {		msg->msg_flags |= MSG_TRUNC;		copied = len;	}	err = skb_copy_datagram_msg(skb, 0, msg, copied);	if (unlikely(err)) {		kfree_skb(skb);		return err;	}	sock_recv_timestamp(msg, sk, skb); 	serr = SKB_EXT_ERR(skb); 	if (sin && ipv6_datagram_support_addr(serr)) {		const unsigned char *nh = skb_network_header(skb);		sin->sin6_family = AF_INET6;		sin->sin6_flowinfo = 0;		sin->sin6_port = serr->port;		if (skb->protocol == htons(ETH_P_IPV6)) {			const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),								  struct ipv6hdr, daddr);			sin->sin6_addr = ip6h->daddr;			if (inet6_test_bit(SNDFLOW, sk))				sin->sin6_flowinfo = ip6_flowinfo(ip6h);			sin->sin6_scope_id =				ipv6_iface_scope_id(&sin->sin6_addr,						    IP6CB(skb)->iif);

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